Bond dissociation enthalpy group 1 metals

This monograph contains enthalpies of formation, heat capacities, entropies, and metal-ligand bond dissociation enthalpies of organometallic compounds of transition and main group elements. 

Bond dissociation enthalpies (BDEs see Box l.l) for transition metal o-organyls appear at present to fall within the quite wide range of 70-330 kJ mol-1, i.e. a range comparable to those of main group alkyls. It should be noted, however, that transition metals also have the possibility of including a 7t-component when the carbon is sp2 (alkylidenes, alkenyls, acyls) or sp hybridized (alkylidynes, vinylidenes, alkynyls), thereby leading to larger BDEs. 

The metal-methyl mean bond dissociation enthalpies in the main-group homoleptic molecules, MMe , vary from 131 kJmoF in ZnMc2 to 283kJmoF in AlMc3. Thus, the above value for Z) (M-Me) in a transition metal complex is not particularly high, suggesting that many cootdinatively unsaturated transition metal complexes would activate methane. 

The effect of methyl groups in cyclopentadienyl rings on metal-ligand bond dissociation enthalpies is predicted to be small. 

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